The present invention relates to a device for assembly of tubular carrier elements, for example tubular channelless carriers, on the circumference of which a functional layer can be made in the form of a photoelectric layer.
U.S. Pat. No. 5,215,013 refers to device for noise damping in the case of covering the peripheral area of a press cylinder with a tubular rubber blanket. This device preferably is used on the press of an offset press, which is equipped with channelless press cylinders. The rubber blanket is expandable in the circumferential direction, for which a pneumatically generated pressure can act on the inside of the rubber blanket sleeve. Then the expanded rubber blanket sleeve is pushed laterally over the surface of the cylinder. The rubber blanket sleeve is provided with a damping ring for damping the noise, which is caused by the lateral emergence of the compressed air. The high-frequency noise, generated by oscillations of the rubber blanket sleeve which is under pressure, is damped by the damping ring. The cylinder surface is provided with exit holes, which create and maintain the air cushion at the time of pursing the rubber blanket sleeve over the surface of the cylinder, at the place at which the rubber blanket sleeve is set laterally on the cylinder surface for pushing.
U.S. Pat. No. 5,649,267 refers to a cylinder arrangement which can be used in a press unit. An essentially tubular element, on the surface of which a toner image can be generated, is used on the cylinder arrangement which is made essentially drum-shaped. The drum surface includes open ends, the flat sides of which are supported by disk-like peripheral areas supporting the lateral surface. The flat sides, with which the openings of the cylindrically configured surface can be closed, are cooled before assembly, in order then to be let into the openings of the surface. The flat sides, which are shrunken into the cylinder surface ends in this way, in this case are provided with shaft bearings. A shaft passing through the drum arrangement in the axial direction is received in the shaft bearings. The eccentricity of the drum casing can be preset relative to the rotation axis by the adjustment screws provided on the flat sides.
In the case of electrographic press units, wear of the functional layer takes place on cylinders, the surface of which can be provided with a functional layer, for example a photoelectric layer. This wear of the functional layer makes replacement of the functional layer necessary. In order to be able to perform the replacement, the sleeve which holds the functional layer in each case is changed inside or outside the press unit. In this case a positionally correct pushing of the cylinder sleeve carrying the functional layer is mandatory.
In view of the solutions known from the prior art and the technical problem indicated, the object of the invention is to make reliable assembly of a cylinder covering on a carrier cylinder possible.
According to the invention this object is achieved by the features of Patent claim 1.
The advantages resulting from the solution proposed according to the invention are to be seen above all in the fact that the covering to be applied can be positioned laterally almost seamlessly on the surface of the carrier cylinder by setting the assembly aid on a flat side of the carrier cylinder. The air cushion generated by a pressure medium, supporting the process of mounting the tubular carrier, is created only when the assembly aid is positioned on the stop surface of the carrier cylinder correspondingly provided therefor. The surface of the tubular carrier to be mounted is protected effectively on the assembly aid, since a cover overlapping the surface of the covering tubular carrier is provided.
In a further configuration of the concept on which the invention is based, in each case switch elements for switching the pressure medium on and off can be provided on the carrier cylinder or in the assembly aid. This assures that the pressure medium is applied only when it is also actually necessary, namely during the process of positioning the tubular carrier to be applied laterally onto the surface of the carrier cylinder.
The circumstance that the action of exit openings for the pressure medium in each case exerted on the peripheral surface of the assembly aid and on the circumference of the carrier cylinder takes place only when assembly aid and carrier cylinder lie against one another on a stop surface is particularly advantageous. The correct arrangement of the assembly aid on the carrier cylinder can be achieved by having one of the bearing pins of the carrier cylinder serve as a centering element. The bearing pin serving as a centering element works together with a receptacle provided inside the assembly aid, which in a preferred configuration can be made as a hole extending along the rotation axis of the assembly aid and the carrier cylinder. The receptacle can be made both parallel to the rotation axis of the assembly aid and the centering element; the receptacle can be made just as well coaxial to the rotation axis of the carrier cylinder and assembly aid. In order to assure the centering of the assembly aid on the bearing surface of the carrier cylinder, the receptacle can be provided with an opening on a flat side, in which an end of the bearing pin functioning as a centering element can be received. The accuracy and duration of the centering is increased significantly by having the receptacle overlap the end of the bearing pin with a covering area, so that the centering of the assembly aid can be maintained while it lies tight against the bearing surface. The assembly aid includes an outlet opening into its lateral surface for a pressure medium, wherein the latter opens in particular in an area under cover protecting the tubular carrier. A ring slot extending over the axial length is made between the lateral surface of the assembly aid and the cover for protecting the surface or the tubular carrier.
In order to assure that the pressure medium acting on the carrier cylinder and assembly aid can be switched on and off in the case of axial positioning of the tubular carrier, an operating element is made on the assembly aid. The operating element, for example made as a pin, penetrates a flat side of the carrier cylinder in the case of contact of the assembly aid with a bearing surface on the carrier cylinder, and causes a pressure medium to flow out into the corresponding outlet openings on the lateral surface of carrier cylinder and assembly aid.
The operating element made, for example, as a pin can be operable also in the axial direction; operation of the same in the radial direction is equally well conceivable. In the case of pin-shaped configuration of the operating element provided on the assembly aid the latter penetrates the flat side in the case of installation of the assembly aid on a bearing pin of the carrier cylinder and corresponding centering by holding on a bearing pin of the carrier cylinder in such a way that the end of the operating element is in contact with a conical switch element, which operates a valve provided with the carrier cylinder. The pressure provided via a pressure medium line is directed into the carrier cylinder opening via a connection through the bearing pin turned away from the bearing surface onto the surface of the carrier cylinder and assembly aid. In addition, outlet openings are made in the mounting area of assembly area and carrier cylinder, which both open into the hole which is penetrated by the operating element and into which the pressure medium flowing out from the pressure line released by the valve arrangement in the carrier cylinder opens and which acts upon the peripheral surfaces of the two components mentioned.
The device proposed according to the invention advantageously can be used in a press with which both a web-like printing material as well as a printing material in sheet form can be printed on one or both sides. The press can be part of a printing press, which contains one or more presses, a toner image being generated on the lateral surface of the channel-less tubular carrier form to be mounted.